Weiland, A. W., and K. J. Gremillion. “Patterns of Variation in the Seed Morphology of Iva Annua Var. Macrocarpa, an Extinct North American Domesticate”. Ethnobiology Letters, Vol. 9, no. 2, May 2018, pp. 75-89, doi:10.14237/ebl.9.2.2018.990.